The present invention relates to 3rd generation mobile telecommunication systems including High Speed Downlink Packet Access (HSDPA), as specified, e.g., in the documents 3GPP TR 25.848 “Physical Layer Aspects of UTRA High Speed Downlink Packet Access” or 3GPP TR 25.899 “High Speed Downlink Packet Access (HSDPA) enhancements” both issued by the 3rd Generation Partnership Project. In HSDPA every user is allocated a dedicated channel (DPCH) in both directions to exchange higher layer signaling information between user equipments (UE) and Radio Network Controller (RNC). As there can be a large number of HSDPA users in a cell, this might lead to a waste of the OVSF (Orthogonal Variable Spreading Factor)-codes in the downlink. In order to save such OVSF-codes the concept of Fractional Dedicated Physical Channels (F-DPCH) has been introduced, e.g. in said document 3GPP TR25.899. Several HSDPA users are to share the same F-DPCH on which only dedicated pilots and TPC-commands are transmitted, i.e. the DPCCH (TPC and pilot bits) of several users are time multiplexed on one OVSF-code. The corresponding SRBs (Signalling Radio Bearers) are mapped onto HSDPA leading to a more efficient usage of the channelisation codes.
The F-DPCH, however, does not contain any transport channel, which implies that the outer loop power control cannot be based on the transport block errors. One solution to this problem could be that the user equipment derives the SIR (Signal-to-Interference Ratio) target for the inner loop power control based on the uplink TPC Bit Error Ratio (UL TPC BER) (UL TPC commands are transmitted on the downlink). This is applicable for a single link case. However, in soft handover the user equipment may not experience the same UL BER on different radio links and, thus, it is not specified how a user equipment in soft handover derives the SIR target for the inner loop.
The user equipment may set its SIR target in a way that all radio links are able to maintain the TPC BER below or equal to the target TPC BER that is set by the network. This means that the user equipment derives its SIR target for the inner loop based on the worst link, i.e. the link having the highest TPC BER.